浙江省为害水稻的螟虫主要为三化螟和二化螟,其分布与耕作制度有着密切关系。杭州、嘉兴、湖州平原晚粳稻区在改制前向以三化螟害为主,是本省螟害严重区域。自改制后到1956年约有25%单季晚粳稻改种连作稻,又原来混栽有一部分早中稻,因增加了混栽程度,使第一代螟蛾可以直接飞入早稻本田产卵,由于螟蛾有趋嫩产卵习性,第二代飞往单季晚稻田产卵,第三代集中连作晚稻田产卵,三代的发生期都碰上了最适宜其生育繁殖的分蘗期,因此, The main stem borers and the stem borers in Zhejiang Province are rice stem borers. Their distribution is closely related to the farming system. Late Japonica rice areas in Hangzhou, Jiaxing and Huzhou Plain were dominated by the stem borer attacker before the system was reformed, which is a serious area for stem borer damage in the province. Since the system reform, about 25% of the single-season late japonica rice has been planted as continuous cropping rice in 1956, and a part of early-middle-aged rice has also been mixedly mixed. As the degree of planting is increased, the first generation of moth can fly into the early rice and honda spawn, Due to the tendency of spider moths to have spawning habits of spawning, the second generation flew to single-season late rice so as to lay eggs. The third generation concentrated even for late-rice paddy spawning. The occurrence of the third generation all ran into the most suitable tillering stage of fertility and reproduction ,